Slack-adjuster for car-brakes



3 Sheets Sheet 1.

(No Model.)

B. A. PARKE.

SLACK ADJUSTER FOR GAR BRAKES.

No. 480,341. Patented Aug. 9, 1892.

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3 Sheets-Sheet 2.

(No Model.)

B. A. PARKE.

SLACK ADJUSTER FOR GAR BRAKES.

No. 480,341. Patentd Aug. 9, 1892..

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(No Model.) 3 SheetsSheet 3. R. A. PARKE.

SLACK ADJUSTER FOR GAR BRAKES. v Patented Aug. 9, 1892.

UNITED STATES PATENT OFFICE.

ROBERT A. PARKE, OF NEW YORK, N. Y., ASSIGNOR OF ONE-HALF TO H. H.WESTINGHOUSE, OF PITTSBURGH, PENNSYLVANIA.

SLACK-ADJUSTER FOR CAR-BRAKES.

SPECIFICATION forming part of Letters Patent No. 480,341, dated August9, 1892.

Application filed February 13, 1892. Serial No. 421,384. (No model.)

To all whom it may concern: application of my improved automatic slack-Be itknown that I, ROBERT A. PARKE, a adjuster to the ordinary form ofpassengercitizen of the United States, residing in the car truck. Fig. 2is a plan View illustrating 55 city, county, and State of New York, haveinthe construction and arrangement of some of vented certain newanduseful Improvements the parts shown in Fig. 1. Fig. 3 is a side inCar-Brake Apparatus, of which the followelevation illustrating theapplication of my ing is a specification. improvement to the ordinaryform of freight- Myinvention relates to the apparatus used car truck.Fig. 4 is a plan view illustrating 60 upon car-trucks for theapplication of a brakthe construction and arrangement of some of IO ingor retarding force to the car when in mothe parts shown in Fig. 3. Figs.5 and 6 are tion and to the method of compensating for side elevations,partly in section, of modified the lost motion in such brake apparatusarisforms of my improvement. Fig. 7 is a plan ing from the wearing awayof the surface of view of the construction shown in Fig. 6. 65 the brakeshoes or blocks through repeated Fig. 8 is a cross-section on the linewas of Fig. applications to the wheels for reducing the 5. Fig. 9 is asimilar view of a modification. speed of the car. It is well understoodthat Figs. 10 and 11 are side elevations, partly in where thebrake-shoes are applied to the section, of modified constructions of myimwheels by the movement of the piston of an provement. 7o air-cylinderthrough intervening mechanism Like numeralsindicate like parts in thesevof levers and rods or by any other device eral figures.

wherein the primary moving member of the Referring now to Figs. 1 and 2,1 indicates motor has a limited movement the wearing the brake-rod,which is pivotally connected to away of the shoes and the consequentinthe upper end of the live-truck brake-lever2 75 creased movement ofthe parts increase the by means of the pin 3. The brake-rod is also 2 5movement of the primary moving member of connected to the primary movingmember of the motor toward the limit at which the mothe motor used forapplying the brakesuch, tor ceases to be effective. It thus becomes forexample, as the piston of a fluid-pressure necessary to prevent suchextreme movement brake-cylinderby meansof such intervening 80 of theprimary moving member of the motor levers and connections as maybeincident to by compensating at some point in the brake the particularstyle of motor and source of apparatus for the increased movement of thepower used, as will be clearly understood by a parts of such apparatusdue to the wear of person skilled in the art. The live-lever2 is thebrake-shoes. Where human vigilance is secured by a pin 4 and asuitableclevisto one 8 depended upon for manually making such of the brakebeams, to which are attached the 5 compensation, accidents to railwaytrains brake-shoes 5 of one pair of wheels. The have occurred fromneglect to properly make dead-lever 8 is similarly secured by means ofsuch compensation. the pin 9 and a suitable clevis to the other Variousautomatic devices to compensate brake-beam, which carries thebrake-shoes 5 90 for the wear of the brake-shoes by taking up of theother pair of wheels. The lower ends the excessive slack movement of theappaof the levers 2 and S are connected together ratus at some pointthereof have been proby means of the pins 7 and the rod 6, which posedand used for the purpose of averting is familiarly known as theconnecting-rod. the danger growing out of neglect to adjust The upperend of the dead-lever 8 is inclosed 5 the slack by hand. These automaticdevices and guided in its movements by an automati- 5 are calledautomatic slack adjusters or cally-adjustable abutment 12, having a stemslack take-ups. My invention consists in or rod 10, which is supportedby and has a free an improved automatic slack-adjuster. axial movementin a casing 11, secured to the To enable others skilled in the art tomake truck-timber 13. The guide 12 is recessed to I00 and use myinvention, I will now describe it receive the upper end of thedead-lever 8, and by reference to the accompanying three sheets itsfunction is to abut against and force said of drawings, in which upperend forward from time to time to take Figure 1 is a side elevationillustrating the up the slack of the brake apparatus, and this functionof the abutment in conneection with its capability of progressiveautomatic adjustment, forms the important feature of my improvement.

The casing 11 is divided into two compartments, and when the devices arein their normal position, as illustrated in Fig. 1, the rod 10 extendslongitudinally throughout both compartments. In the, inner compartmentisa sliding sleeve or box 14, which surrounds and is supported by a rod10. In the sleeve or box 14 is a pawl or clutch 15, which rests on topof the rod 10 and is pivoted in the sleeve 14 in such a manner that itwill slide freely along the surface of the rod when moved in a directionaway from the dead-lever 8, but when moved in the opposite directionwill bite upon the rod and clamp it rigidly against the lower inner faceof the sliding sleeve 14, so that the sleeve 14 cannot be moved towardthe dead-lever S withoutdrawing the rod 10 with it.

In the outer compartment of the casing 11 are washers 18, which looselyencircle the rod 10. These parts are more clearly shown in the enlargedView, Fig. 5. The washers 18 are normally supported by the rod 10, butwhen the rod is moved axially toward the deadlever 8 the washers at theright end of the casing 11 successively lose the support of the rod andfall downward in the casing 11, as illustrated in Figs. 5 and 8, to sucha position that their solid portions are interposed between the end ofthe rod 10 and the solid end of the casing 11, so as to lock the rod 10in the position to which it has been moved toward the dead-lever 8. Thismovement of the rod 10 has the effect of advancing the abutment 12 to anew position and causing it to force the upper end of the dead-lever 8forward a corresponding extent.

Removably secured to the brake-rod 1 is a carrier 19, which looselysupports a rod 20. One end of the rod 20 is loosely but durably securedto a rod 22 and the other end terminates in a head or collar 21. One endof the rod 22 is provided with a clevis 23, which is pivotally securedto the upper end of the clutch 15 bya pin 17,and the other end passesthrough a guide 24,secured to the truck-frame, and terminates in a heador collar 25. Arranged between the guide 24 and the collar 25 is aspring 26, which encircles the rod 22. The carrier 19 is secured to thebrake-rod at a point which will permit the desired definite length ofmovement of the brake-rod and its connections to the right to take placebefore the carrier engages the collar 21 of the rod 20.

The operation is as follows: hen the brakes are applied by the motor,the brakerod 1 is caused to move toward the right, together with theupper end of the live-lever 2, thereby drawing the brake-beam attachedto the lever 2 to the wheels, and at the same time causing theconnecting-rod 6 to move to the left, drawing the brake-beam attached tothe dead-lever 8 toward its pair of wheels, thus applying thebrake-shoes to all the wheels. Should this result be obtained without asuificient movement of the brake-rod to the right to cause the carrier19 to engage the collar 21, no further movement of the apparatus willtake place. As the brake-shoes wear, however, from repeated applicationsto the wheels, the brake-rod 1 is permitted to move a greater distanceto the right at each successive application of the brakes, until finallythe carrier 19 will engage the collar 21 of the rod 20 and cause therods 20 and 22, clutch 15, and sleeve 14 to be moved to the right andthe spring 26 to be compressed. When the brakes are again released, thebrake-rod 1 will return to its normal position, (shown in Fig. 1,)disengaging the carrier 19 and collar 21 and permitting the spring 26 toforce the rod 22 to return to its normal position. (Shown in Fig. 1.)The return of the rod 22, however, is accompanied by the return of theclutch 15 and sleeve 14, which grip the rod 10 firmly between them,causing the abutment 12 to also move to the left until the sleeve 14comes to its normal position against the inner end of the casing 11, asshown in Fig. 1. As the rod 10 moves to the left the upper end ofdead-lever 8 is carried with it, and one or more of the washers 18 dropoff the end of the rod 10 and prevent the return of the rod 10 to theposition shown in Fig. 1, when the brakes are again applied. Themovement of the upper end of the dead-lever 8 to the left causes theapproach of both the brake-beams with their brake-shoes toward thewheels, in the same way that the movementof the upper end of the1ive-lever 2 to the right effects the application of the brake, and thusthe slack of the parts due to the wear of the brake-shoes is reduced ortaken up. In this manner all that portion of the movement of thebrakerod 1 to .the right in the application of the brakes which exceedsthat necessary to cause the carrier 19 to engage with the collar 21 iscommunicated to the rod 22 and sleeve 14, and when such excess ofmovement of the brake-rod 1 becomes equal to the thickness of one of thewashers 18 the return of the rod 22 by means of the spring 26 will causethe rod 10 to be moved to the left sufficiently to drop one washer fromits end. The distance through which it is desired that thebrake-rod 1shall move in the application of the brakes having been determined, thecarrier 19 is secured to the rod 1 at such a point that it must traversesuch distance before engaging the collar 21. As the brake-shoessubsequentlywear in the application of the brakes, the distance moved bythe brake-rod 1 can exceed that selected only by such an amount as willcause the rod 10 to drop one washer upon the release of the brakes,which will thus set the abutment 12 forward a corresponding extent, andthereby take up the slack of the brake-shoes and cause the travel of thebrake-rod 1 to become normal again until sufficient further wear of theshoes to drop another washer has taken place.

The construction in Fig. 3 differs somewhat from that in Fig. 1. Here arod 27 is pivotally secured to the brake-rod 1as, for instance, by meansof a clevis and pin 3. It is supported by and guided in the casing 11and also passes through a projecting arm of the clutch 15 and terminatesat its other end in a head or collar 28. The spring 26 encircles the rod27 and is confined between the casing 11 and the projecting arm of theclutch 15. In its operation the brake-rod 1 is moved to the right,applying the brake-shoes to the wheels and carrying the rod 27 with it.If the movement of the brake-rod 1 in applying the brakes is increasedby the wear of the brake-shoes, the collar 28 will engage the clutch 15and carry the clutch 15 and sleeve 14 to the right, with the rod 27,through such a distance as the movement of the brake-rod 1 exceeds thenormal distance required to set the brakeshoes, the clutch 15 and sleeve14 sliding freely over the rod 10. When the brakes are released by themovement of the brake-rod 1 to the left, the spring 26 forces the clutch15 and sleeve 14 in the same direction, causing them to engage the rod10 and force the abutment 12 against the dead-lever 8, carrying itforward until the sleeve 14 comes in contact with the end of the casing11 and a washer is dropped off the end of the rod 10, preventing itsreturn and locking the abutment in its new position.

In the modification shown in Fig. 5 the carrier 19 is loosely connectedto the clutch 15 by a chain 29, so that the desired movement of thebrake-rod 1 to the right before engaging the clutch 15 is securedthrough the slack of the chain 29. In this construction the spring 26 isconfined between the casing 11 and the collar 25 on the rod 22. In Fig.5 some of the washers are shown in theirlower position, the rod 10having been moved to the left, so as to set the abutment12 forward andadvance the upper end of the dead-lever 8, and thereby take up the slackin the brake apparatus. The bottom of the compartment which contains thewashers 18 is slotted, as at 30, to enable the-washers to be lifted totheir upper position (by inserting a fiat instrument or otherwise) whenit is desired to move the rod 10 back to its normal position.

for the purpose of replacing worn brakeshoes with new ones. Thesections, Figs. 8 and 9, showthat the rod 10 may be either round orsquare in cross-section. It may be of other shapes, if desired.

Figs. 6 and 7 show another modification, in which a collar on thebrake-rod 1 is substituted for the carrier 19 of the former figures. Inthis instance the rod 22 is loosely suspended from the brake-rod 1 by aloop at its outer end, while its inner end is secured to the sleeve 32by the pin 17. Pivoted to the casing 11 is a stirrup 31, the outer endof whichenqircles the rod22. The spring 26 is secured between thestirrup 31 and the collar 25 on the rod 22. The rod 10 is serrated andthe sleeve 32, which fits loosely upon it, has corresponding serrationson its upper inner surface at the left, while its inner surface isotherwise plain. Pivoted in the casing 11 is a pawl 33, having aserrated face for engaging with the serrations of the rod 10. This pawlis so placed as to permit of the free movement of the rod 10 toward thedead-lever, but to check a movement in theopposite direction. It is inthis instance the equivalent for the washers in the former figures, itsfunction being to hold the abutment 12 firmly in its adjusted positionagainst the backward thrust of the dead-lever. In the operation of thismodified form of the apparatus when the collar 19 of the brake-rod 1engages the rod 22 and moves it to the right the spring 26 is compressedand the left end of the sleeve 32 is lifted, so as to disengage itsteeth from the serrations of the rod 10 and cause it to slip along therod to the right. When the brakes are released, the collar 19 becomesdisengaged from the rod 22, releasing the spring 26, which forces theteeth of the sleeve 32 into the serrations of the rod 10 and causes therod to be forced to the left until the sleeve comes in contact with thecasing 11. The pawl 32 then engages the rod 10 and prevents its movementto the right when the brakes are next applied.

Fig. 11 shows a modification of the ,construction shown in Fig. 6, inwhich the spring 26 is secured in the casing 11 between the outer wallof the casing and the sleeve 32. In this construction the stirrup 31 isdispensed with.

Fig. 10 illustrates another modification of my improved appliance, bywhich the slack of the brake apparatus is taken up at the top of thelive truck-lever 2 instead of at the top of the dead truck-lever 8, asbefore described. In this construction the abutment 12 on the inner endof the rod 10 is provided with a vertical arm 37, to which is pivoted apawl 38. The rod 10 passes through the tube 34 and at its outer endterminates in a head or collar 35. The exterior of the tube 34is'serrated throughout its length and rests loosely in the casing 11, insuch position as to be engaged by a pawl 33, which is pivoted in thecasing 11, and is arranged to permit the movement of the tube toward thebrake-lever, but to prevent its movement in the opposite direction. Therod 10 slides freely through the tube 34 and is of sufficiently-greaterlength that the movement necessary for setting the brakes with new orunworn shoes can take place without the collar 35 engaging the end ofthe tube; but if there is slack in the brake apparatus, caused by thewearing of the shoes, the collar 35 will engage the rear end of the tube34 before the brakes are fully applied. The upper end of the projectingarm 37 is recessed or slotted, so that the brake-rod 31 may pass looselythrough it, and the pawl 38 is so arranged as to slip over the brake-rodduring its backward movement, but to engage with it during its forwardmovement. The brakerod also extends through the casing 11 and isprovided with a head or collar 40 at its outer end, and the spring41,which encircles the brake-rod, is confined between the casing 11 andthe collar 40. When the brake rod moves to the right, the pawl 38engages its serrated portion, so as to draw the arm 37 and abutment 12against the upper end of the live-lever 2, so as to apply the brakes. Ifthe brake-shoes are worn and there is slack in the apparatus, so thatthe movement of the brakerod is greater than the normal distance betweenthe collar 35 and the rear end of the tube 34, such excess of movementwill cause the collar 35 to engage the end of the tube 34 and force thetube forward toward the brakelever, this movement of the tube beingpermitted by the pawl 33. When the brakes are released, the pawl 33engages the tube and prevents its return movement, so that the rod 10and live-lever 2 cannot return to the normal positions shown in Fig. 10,their movement being limited by the new position of the tube 34. Thespring 41 causes the brake-rod 1, however, to move back to its normalposition, the pawl 38 permitting such movement. The extent to which thetube 34 is advanced is equivalent to the amount of slack in the brakeapparatus, so that the abutment 12, which limits the backward movementof the brake-lever 2, is adjusted to a new position, which makes thebrake apparatus eifective with the normal movement of the brake-rod. Theupper end of the brake-lever, through which the slack is taken up, maybe secured by a pin to abutment 12, as shown in Fig. 6, or it may restloosely within its slotted end, as shown in other figures. The functionof the abutment 12 is the same in both cases. The brake-rod 1 isintended to represent, broadly, the power connections between thebrake-motor and the live truck-lever, and is designed to cover andinclude such other forms of power connections which directly orindirectly transmit the power from the prime motor to the livetruck-lever as will cause my improved devices to operate in the mannerdescribed to automatically take up the slack in the brake apparatuscaused by the wear of the brakeshoes and wheels.

I am aware that slack-adjusting devices have been applied to theconnecting-rod 6, which insuch devices is madein two or more pieces, andthe slack of the brake apparatus is compensated by a shortening orlengthening of such connecting-rod 6. My invention is different from andmuch better than such devices, because, first, the connectingrod 6 isalways subjected to the heaviest strains brought upon the brakeapparatus, while connections to the upper ends of the truck-levers aresubjected to the lightest strains, so that there is less danger ofderangement of the adjusting apparatus when it is attached to the upperend of a truck-1ever than when it is attached to the connecting-rod;second, should the adjusting apparatus break, the slack can be adjustedby hand at the upper end of the truck-lever, while if attached to theconnecting-rod it would destroy the operativeness of the brakes and beliable to cause serious accidents by the parts falling upon the track;third, when it is necessary to return the adjusting apparatus to itsnormal position for the purpose of applying new brake-shoes it isreadily accessible at the upper end of the truck-lever, while if appliedto the connecting-rod it would be accessible only with diiiiculty;fourth, on account of the much greater movement of the upper end of thetruck-lever than of the lower end in compensating for a given wear ofbrake-shoes the adjustment of the slack at the upper end of thetruck-lever secures a much more uniform travel of the primary movingmember of the motor.

I am also aware that devices have been used for taking up the slack ofthe brake apparatus at the upper end of the truck-lever by means of aratchet-aud-windlass movement. My invention is an improvement upon suchdevices in being more direct, simple, and accessible, and, the movementof the parts being axial, no limit to the movement within that caused bythe full movement of the primary moving member of the motor isencountered, as is the case where the movement of some parts is radial.

In case the construction shown in Fig. 10 is used with a fluid-pressurebrake mechanism in which a spring is arranged in the brakecylinder torelease the brakes the spring 41 may, if desired, be omitted and thereleasingspring in the brake-cylinder be depended on to restore thebrake-rod 1 to its normal position. (Shown in Fig. 10.)

The loose connection referred to in the claims is embodied in the parts19, 20, and 22 in Figs. 1 and 2, the part 27 in Figs. 3 and 4,

the parts 19 and 22 in Figs. 5, 6, 7, and 11,

and the parts 37, 10, and 34 in Fig. 10. The clutch device referred toin the claims is embodied in the parts 14 and 15 in Figs. 1, 2, 3, 4,and 5, the part 32 in Figs. 6, 7, and 11, and the parts 37 and 38 inFig. 10. The locking device is embodied in the washers 18 in Figs. 1, 2,3, 4, and 5 and the pawl 33 in Figs. 6, 7, 10, and 11. The pawls 15 and33 may be made without teeth and be used with a smooth rod, serving tohold it by friction.

I am aware that Patent No. 465,266, dated December 15, 1891,shows anautomatic slackadjuster, consisting of a Windlass which is operated bythe abnormal movement of the brake-rod and a chain extending from saidWindlass to the upper end of the live brakelever, which communicates themovement of the Windlass to the brake-lever, and thereby draws saidlever closer to the wheel of the car, so as to compensate for the wearof the brake-shoes, the said lever being actuated by means of a radiallever and an intermediate pawl and beingheld in its adjusted positionsby a suitable holdingpawl. This device, however, differs both inconstruction and operation from my invention in that instead of theWindlass and chain-draft arrangement described in the said patent, withthe numerous parts necessary to such construction, I use anaxially-movable abutment which is external to and has no necessaryconnection with the brake-lever, but which by a positive advancemovement corresponding to the wear of the brake-shoes, however small,takes up any slack which may occur in the brake apparatus as the resultof such wear. It is not only positive, but by reason of its simpleconstruction and its being mounted independently upon the truck-frame itis not liable to get out of order, and if it shonldit may be easily andquickly repaired or replaced.

I am aware that Patent No. 428,744, dated May 27, 1890, shows acontractible lower connecting-rod provided with ribs and a series ofwashers mounted on the rod and supported by the ribs in an elevatedposition, so that when slack occurs the washers shall drop one by oneoff of the ribs and down onto the body of the rod between the ends ofthe ribs and the end of the case that incloses the washers, and therebycompensate for the wear of the brake-shoes. I am also aware that PatentNo. 453,062, dated May 26, 1891, shows an extensible lowerconnecting-rod and a series of liners pivoted to a pintle-rod in suchrelation to the abutting ends of the two sections of the connecting-rodas to swing one by one between the said ends, and thereby compensate forthe wear of the brake-shoes. My stemand-washer device is different fromthese devices both in construction and combination, as it is notinterposed in and forms no part of the system of rods and levers bywhich the brakes are applied, as do said prior devices, but is connectedwith and forms one of the means for adjusting the external abutment,against which one of the brake-levers rests and which holds said leverup to its normal range of movement.

\Vhat I claim as my invention is '1. In an automatic slack-adjuster,abrakerod having a definite normal movement for setting the brake-shoes,in combination with one of the brake-levers and an axially-movableabutment actuated through intermediate mechanism, substantially asdescribed, by the abnormal movement of the brake-rod caused by the slackproduced by the wearing of the brake-shoes, substantially as and for thepurposes described.

2. In an automatic slack-adjuster,thebrakerod having a definite normalmovement for setting the brake-shoes, in combination with one of thebrake-levers, an axially-movable abutment, mechanism arranged betweenthe brake-rod and the abutment and operated in one direction by anabnormal movement of the brake-rod and in the opposite direction by aretracting-spring, whereby the abutment is automatically advanced andforces the brake-lever forward to take up the slack of the brakeapparatus caused by the wear of the brake-shoes, and a lockin g devicefor holding the abutment in its advanced position, substantially as andfor the purposes described.

3. The combination of the brake-rod having a definite normal movementfor settlng the brake-shoes with an abutment having an axially-movablestem, a clutch device capable of a free backward motion on the stem ofthe abutment, a loose connection between the brake-rod and the clutchdevice, and a retracting-spring for actuating the clutch device andcausing it to move the abutment forward to a new position, substantiallyas and for the purposes described.

4. The combination of the brake-rod with the loose connection, theabutment 12, having a stem 10, a clutch device capable of moving freelyin one direction on the stem, a spring for moving the clutch device andstem in the opposite direction, and a locking device for holding theabutment in its adjusted position, substantially as and for the purposesdescribed.

5. The combination of the brake-rod with the carrier or collar 19, theloose connection 22, the abutment-stem 10, and the clutch de vicemounted on the rod 10 and moved by the connection 22 in one directionand a spring 26 in the other direction, substantially as and for thepurposes described.

6. In an automatic slack-adjuster, an abutment having a stem by which itis supported on the truck-frame, in combination with a casing containingwashers, which, when the abutment is adjusted forward to take up theslack of the brake-lever, fall one by one back of the end of the stemfor the purpose of bolding the abutment in its adjusted position,substantially as and for the purposes described.

7. The combination of the abutment 12, stem 10, casing 11, and washers18, substantially as and for the purposes described.

8. The combination of the abutment 12, stem 10, and washers 18 with thecasing 11 for containing and holding the washers, provided with a narrowslot 30 for the insertion of an instrument to raise the washers in thecasing, substantially as and for the purposes described.

9. The combination of the brake lever, abutment 12, and stem 10 with thesliding box or sleeve 1 1 and pawl 15, substantially as and for thepurposes described.

In testimony whereof I have hereunto set my hand this 12th day ofFebruary, 1892.

ROBERT A. PARKE.

Witnesses:

O. E. THORNALL, THOMAS B. KERR.

